This invention relates to methods and apparatus for accurate connection of ink-jet printer components, such as ink cartridges, to other ink-jet printer components, such as carriages.
An ink-jet printer produces images and text on a page by firing drops of ink from the printheads of one or more ink cartridges while the cartridges move back and forth across the page. Examples of ink-jet printers include plotters, facsimile machines, and typical computer-attached ink-jet printers. The page on which a printer prints may be any sheet material, such as paper, mylar, foils, transparencies, card stock, etc.
The ink supply of an ink-jet printer is limited. Thus, many cartridges are designed to be replaceable. A user simply replaces the old, empty ink cartridge with a new, full ink cartridge. In these so-called cartridge-type printers, the cartridges are manufactured as a unit that includes a printhead and an ink reservoir. Thus, the cartridges are seated in a carriage that travels back and forth across the page during the printing operation.
In some designs, the ink reservoir is a container that may be disconnected from the printhead, which remains installed on the carriage while the container is replaced.
In so-called off-axis printers, only a printhead moves across the page. Ink is delivered to an inlet port in the printhead via a flexible, ink delivery tube that extends from a stationary ink reservoir. Typically, the ink reservoir is mounted to the printer chassis and may be replaced or refilled when empty. Off-axis printers may be equipped either with a single printhead for monochromatic printing, or with several printheads for color printing. Of course, for color printing, several reservoirs and associated tubes are required, with one set used for each color.
In the ink-delivery systems of off-axis printers, the ink-delivery tube may be permanently connected to the printhead, but this would prevent replacement of the printhead. The printhead may suffer mechanical breakdown or simply wear-out after firing millions of drops of ink. Therefore, the printheads of a typical ink-jet printer are designed to be replaced, as necessary. To this end, the ink-delivery tube may terminate in a needle for piercing a resilient septum that is carried on the printhead and that otherwise seals the inlet port of the printhead. A needle/septum interface mechanism such as this allows for disconnection of the tube and printhead for occasional replacement of the printhead. A similar interface may be employed where the ink-delivery tube joins the stationary ink reservoir.
The supply of ink in reservoirs or containers used in cartridge-type or off-axis type printers may be replenished in refill stations that are peripheral components of the printer system.
Irrespective of the nature of the removable ink-jet printer component (ink cartridge, reservoir or printhead, for example), it is desirable to ensure that those components are accurately connected in the printer. That is, a component such as an ink cartridge must be properly seated in the carriage. Also, in instances where a carriage is designed to carry more than one cartridge, it is important that the ink container having the correct print characteristic (such as ink color) be located in the correct position in the carriage, so that the printer controller can precisely control the printing of drops of that color.
This proper seating and positioning requirement also applies to off-axis printers, especially where several reservoirs and associated ink-delivery tubes are involved.
In the past, various mechanical latches, datum features, and/or electrical identification techniques have been employed for ensuring that a replaceable ink-jet printer component is properly connected in the correct location.
The present invention may be used in lieu of, or in conjunction with, the prior approaches and primarily features the use of magnetic force to enhance the strength and accuracy with which replaceable components are connected in a printer.
As one aspect of the present invention, a component such as an ink cartridge is provided with magnetic members. A corresponding component is also provided with magnetic members so that magnetic attraction between the two components provides or enhances the connecting or clamping force between those components.
As another aspect of the present invention, the magnetic members on one component (such as the ink cartridge) are arranged in a particular pattern that indicates a print characteristic of the cartridge. The print characteristic may relate to the color of the ink in the cartridge, or to other characteristics, such as the reservoir size of the cartridge that is used. A corresponding pattern is provided in the carriage. The pattern is such that magnetic force will attract a particular cartridge to the correct mating location in the carriage. This magnetic attraction is provided as tactile feedback to the user in the course of seating the cartridge in the correct location in the cartridge. The other mating locations in the carriage (that is, locations intended for cartridges having other print characteristics, such as other colors) do not have patterns corresponding to that particular cartridge and thus do not provide magnetic attraction when one attempts to connect that cartridge in one of the other mating locations. This lack of attraction is also felt by the user as tactile feedback that alerts the user to the attempted, improper placement of the cartridge.
In one preferred embodiment of the invention the mating locations of the carriage are provided with various patterns of magnetic member arranged to provide a magnetic repulsion (easily sensed by the user) when one attempts to connect one component at an incorrect location in the printer.
In yet another embodiment, the proximity of a magnetic member on one component is detected by a sensor on the other component. The sensor output is provided to the printer controller for conversion into, for example, an audible signal to the user for confirming that the components are properly aligned and/or connected.
Other advantages and features of the present invention will become clear upon review of the following portions of this specification and the drawings.